Question on Compressibility Check

[MePHisto]

Hi guys, first of all my congratulations for the work you are doing
It's VERY great and it helped me a lot with my rippings :D

Maybe this question has already been answered but I didn't found anything on this forum (this doesn't mean it's not here...)

I can't understand why I have two different results from the compressibility check if I run it:
1. with a resolution equal to 640xYYY and I go down to 512xYYY
2. directly to 512xYYY
...of course using the same vobs :p

That is very strange to me and maybe you can help me in understanding
Not saying it's wrong, just would like to understand why...

Another info...if possible...I have read a lot of posts regarding GKnot (why it is not an open source project, etc...)
I (but I'm not the only one) am hoping that in future GKnot will natively support XviD, and I am hoping that a new version will be available soon
I heard a new version, completely new, is under development and I am waiting for it!!! :rooleyes:

Is there anything you can anticipate?
:cool:

[jggimi]

To answer your question on differences on compressibility test results:

A calculated load percentage based on a simplistic model (from moving the resolution slider) will often produce somewhat different results from a direct measurement of compressibility. That's because the compression changes based on the content's impact on resolution cannot be modelled.

The percentages are usually fairly close, though.

It is recommended that when accurate load factors are needed, to re-run a compression check with every resolution change, prior to a full encoding.

[manono]

Hi and welcome to the forums-

The only thing I know about future versions of GKnot, is that they will be much more configurable. As for XviD compatability-XviD changes so much (they're in the process of implementing B-Frames and Q-Pel, for example), that until some sort of final release is available, there's not really any way to make GKnot support it. But I read that by the end of the year there should be some sort of Version 1 of XviD available, and then maybe GKnot will be able to support it.

[MePHisto]

OK, thanks for the answers (sorry if this post will arrive twice...maybe I've done something wrong the first...)

I'm satisfied :)

Basically I've to run the comp. check the first time, adjust the size, and the re-run it (and repeat the operation until I'm satisfied with the values)

It just takes time but if it gives better results...it's worth it ;)
great

[Swan]

Originally posted by manono

available, there's not really any way to make GKnot support it. But I read that by the end of the year there should be some sort of Version 1 of XviD available, and then maybe GKnot will be able to support it.
One thing I haven't understood about Xvid is if there's any way of performing some sort of compressibility test before encoding?
To decide on the ideal resolution for a bitrate is not easy without some sort of tool.
I know that performing an Xvid compressibility test doesn't work in the current version GordianKnot, but is it possible, using another tool?

I really look forward to the new version of Gordian because the current one is an essential tool. Especially for people like me who don't fully grasp how DivX works, but get great-looking encodes anyway, thanks to Gordian.

/Swan

[MePHisto]

Hi Swan,
before the right people reply I can tell you how I proceed (hoping I'm not saying something completely wrong...)

1st, your experience, this can't be replaced by any tool
Anyone disagree?

2nd, try having a comp. check with divx 5.xx and (only after) compress your media with xvid...this is not always working but it's interesting...

3rd...let me say...try with 'AutoDub XP'
Just to be clear, giving all my respect to the Autodub author, this program can't be compared with GKnot (I have tried a lot of programs, and GK is the best, trust me), but it let you perform the 5% check...
After this you use GK/VirtualDub ways to encode...

Hope this helps

[manono]

Hi Swan-

MePHisto's right. I haven't used AutoDub XP, but as long as you have:

SelectRangeEvery(280,14)

at the bottom of the .avs, then after you run the first pass, load the stats file, and GKnot will spit out a percentage. You will have to set up the encoding manually in VDub, but it's no big deal.